A realtime system means its deterministic, it means you should know how long things take to run. They way to do is is to apply a patch to the linux kernel that makes it non-preemptible. To explain – Preemption is the act of temporarily interrupting a task being carried out by a computer system, without requiring its cooperation, and with the intention of resuming the task later.

This is useful for building hardware and robotics, low latency audio and other gpio because there are no surprises when it comes to timing. It seems like something good to try out with the RaspberryPi, because of the GPIO and IOT capabilities.

Bundled with CustomPiOS you can build your customized realtime-kernel device.

Features

Both armv6 and arm v7 are supported! Aka all versions of RaspberryPi to date!

4.9.52-rt37-v7 with PREEMPT kernel

Easy way to set up the network using realtimepi_wpa_supplicant.txt in the boot partition

Today I am announcing a RaspberryPi operating system that addresses a small need we have – Get the RaspberryPi to display a webpage on full screen with no hassle.
The OS is called FullPageOS. And you can download it here.

Why I built it

A friend of mine, Tailor Vijay wanted something to stream video and add titles to it. Also I was looking for a way to start the RaspberryPi with a browser on full screen for a stats screen at work, and apparently the only thing available is complex guides that only partly work on today’s RaspberryPi.

So what I did last weekend is build a distro based off the code of OctoPi, the 3D printer operating system I built. All this distro does is start Chromium at boot on full screen, with a URL of your choice. The url can be changed conveniently from a text file on the /boot FAT folder. So all you have to do is set the wifi and url via text files, boot, and voilà!
Among the minor tweaking is the elusive setting of disabling the screen from blanking.

How to set it up

What’s nice about FullPageOS is that its simple, no need to install packages, just flash it like any distro, set your wifi and URL settings and boot.

Open the FAT filesystem that is mounted as /boot
on the pi

Set the URL you want in the file fullpageos.txt

If you need to set up wifi, set your wifi settings with the file fullpageos-network.txt or any way you want are used to on the RaspberryPI

I will note it was pretty nice get in to this release PiCam support, since I have no camera it required collaboration of both Gina and me, meaning we have a distro now that probably can cope with more hardware than you would have in your average personal configuration.

Also thanks Matvin for the storage, and we also have another mirror lined up in case of a overload, which happened last time.

Update: Dropbox have suspended my Public links due to “extreme traffic activity” so in a few hours I should be syncing the image to other mirrors. Other hosting would be appreciated!

Hey all,

I am happy to say that I am a backer of the Rigidbot 3D printer, (which you can pre-order already), I am expecting it to arrive in August. In the meantime, I have ordered a Raspberry Pi to play with and started visiting a local maker community known as XLN.

This led me to find a really cool project called OctoPrint, which lets you control 3D printers using a Raspberry Pi over a web interface, however people were not installing it on their Pis because there was no out-of-the-box solution. Today I am happy to announce that a solution is here! I give you Octoprint + Rapberry Pi = OctoPi. A raspberry Pi distribution which runs OctoPrint out of the box, with support for time-lapse video on webcams (there is also an experiential version in the works that supports streaming from a raspberry Pi camera).

A computer that is running virtual box and virtualbox-fuse – I will show how to do this in Linux, but windows and Mac can do this too.

A copy of AndoVM – This is the reason we can do this, since android by default does not come with an Ethernet drivers and AndroVM is compiled and distributed to run on virtualbox out of the box (pun intended).

Friends keep coming up to me and complaining that they had to wipe all their phone because of some attempt to do something.
However, if you give me a brand-new phone and throw mine out of a high-building window, I won’t stop you, because I have a copy of my phone at home, from that same morning, and I don’t even have to think about it.

Want to feel free again? Not scared that this small thing you carry in your pocket with all your life gets ruined? Well, here is how you do it:

Things you will need

Your device needs to be rooted – I am afraid thats a requirement for Titanium backup and all programs that back up app data

Titanium backup – You can use the free version for backing up, but for a single-click restore you will need to pay (I bought it and recommended you do even if its the only thing you ever buy on the play store)

rsync backup for Android – This will back up all your photos and data that isn’t part of your apps, if you don’t root but this is all you want to back up, this post might help you too!

A short post to announce a small piece of software I released today on github for the ham radio people.
I give you SvxlinkWrapper, this wrapper sits on top of Svxlink‘s stdout and stdin and processes it with python. Making it easy to add more advance features to Svxlinik. Since Svxlink is written in C++ and takes a while to compile, this wrapper really speeds up development. Furthermore, it uses straight.plugin making its simple to write more modules by extending SvxlinkwrapperModule and placing it in the modules folder.

Currently the to modules that SvxlinkWrapper has are for auto-connect to Echolink nodes on startup and another for a QSO logger for Echolink connections. There is also a module that should let you send commands over the Echolink chat, if you extend it. This lets me open and close repeater connections directly from the Echolink chat box.

Hi all,
As promised in my last post, I have finally finished designing and building a cheap interface to connect ham radios or any other audio device that does not share audio common ground to a PC, including a PTT interface. Price should be around $17 or 60 NIS. The control is done using a USB interface, so unlike most ham radio hardware that uses serial connections, this one is plug and play in modern PCs. The neat thing is that it uses them same commands as a RigBlaster. So this interface works out of the box with common ham radio programs like Echolink and Svxlink. The interface should also work with soundmodem which can be used for X.25 packet digital communications, without any extra hardware (I am still trying to get this to work). This interface could also be used to connect to other devices that don’t share a common ground. For example like phone lines.

Parts you will need

TTL USB Serial interface – The main part is a simple CP2102 $4 controller that can be percussed from ebay. It simulates a serial device, meaning you can still work with older pieces of software with it. Note though you need to solder a cable from the RTS pin on the board, because normally they don’t come with a pre-made pin.

Audio line isolation transformer – This can be easily salvaged from any old dial-up modem. That’s how I get mine, it seems to be much easier to get them off old modems than finding them in electronics shops, plus they are so easily identifiable (just make sure not to break the contacts when you take them out, happened to me twice). If you can’t find any old dial-up modems you can get it from ebay. (more…)

I have been working on getting an Echolink node running on the Jerusalem repeater using Linux. Echolink is a closed proprietary software that lets you connect ham radios to one another and key them across the Internet. Luckily someone wrote a FOSS program called Svxlink, which lets you connect to the Echolink network on Linux., A remote radio control with an echolink server, svxlink-server and an Echolink graphical client, Qtel. I am going to explain in this post how to get svxlink compiled and working (compiling is the hard part). I will also giving out here an Ubuntu package for the lazy ones among you.

I will also add a small section on the physical connection to the radio, an old Icom IC-02AT from the 80s (around my age). (more…)

Hey all,
After a few weeks of bouncing emails with Thomas Perl I am happy to announce that we have a working plugin for his wonderful podcast application called gPodder. With this plugin installed, any mp4 video podcast that is downloaded with gPodder is automatically converted to a format playable by rockbox MPEG player plugin. Effectively meaning seamless sync of video podcasts to any rockbox enabled device. I am specifically using the Sansa fuze player, but just changing the screen resolution at the top of the plugin should make it work with any other rockbox device, and with the right screen size. The final product for me of all this technical stuff is that I can listen to TED lectures in the car. Or using the verb was coined by my friend Uzair “TEDding” from my car.

How to Install

First you should have gPodder installed (available also as “apt-get install gpodder” or any other distribution install equivalent).